During the next year we propose to continue our investigations of membrane-associated transplantation antigens and tumor-specific transplantation antigens. We hope to develop better assays for the cell-mediated "killer" response which we can induce in vitro for both normal and tumor-specific transplantation antigens. We are studying a number of radioimmune assays for both the antigens and the antibodies that rise in response to these antigens whether lytic or not. These assays will be applied to an investigation of the immunopathology of the malignant lymphoblast L-5178y growing in its syngeneic host DBA/2. It has been already demonstrated that L-5178Y has a tumor-specific transplantation antigen, yet the tumor will grow and kill the host from as small a dose as ten cells per animal.